Building blocks for 3D, modular microfluidics

Tech ID: 27079 / UC Case 2016-765-0

Brief Description

Researchers at the University of CA, Irvine have developed modular microfluidic platforms consisting of microfluidic building blocks that can be connected
in various configurations to construct complete microfluidic devices for different applications.

Full Description

Microfluidics is a recently-emerged technology with broad applications in biology, chemistry,
and biomedical engineering. Microfluidics refers to the manipulation of extremely small volumes of fluids. A typical
microfluidic device is essentially a microscale piping network system. The pipes are channels having widths usually
between 10 microns and 500 microns, and the total size of a microfluidic device is often as small as a quarter. Fluid is
introduced into the piping system through inlets, and the flow may be controlled by syringe pumps or pressure regulators.
Compared to traditional laboratory methods, such as mixing fluids in a test tube, the minimal fluid requirements in
microfluidics reduces reagent consumption and experiment time scales significantly. In addition, working at the microscale
enables detection of rare biological signals. For example, microfluidic devices can be used to sort cells by size or electrical
properties, and these methods are used to purify rare cell populations. Further, there are microfluidic devices that generate
microdroplets, which encapsulate samples and greatly enhances the signal to background noise ratio of highly dilute
compounds in the samples. Yet another application of microfluidics is accurately modeling microphysiological systems.
These platforms contain cells and media is flowed through microfluidic channels. The high design flexibility of microfluidics
enables this technology to recapitulate tissue and even organ physiologies at their native microscales. Such in vitro
biological models, called "tissues-on-chips" or "organs-on-chips", are attractive for drug testing and basic biological
research.

The current fabrication paradigm of microfluidic devices results in devices that are highly inflexible post fabrication. In
industrial production, complete microfluidic devices are typically injection molded or hot embossed. Changing the preset
designs require machine re-tooling. In research and development, microfluidic devices are cast from master molds created
via photolithography. Again, there is no design fluidity post-production. On the other hand, in electronics, one can purchase
a number of basic electrical components, such as resistors, capacitors, and op-amps, to construct a variety of electrical
devices. In current microfluidics, there is no such standardized and mainstream modularity.

The solution is to create a library of basic modules that can be connected in various combinations to create a variety of
different designs. Having such a modular microfluidics platform enables efficient expansion or integration of existing
architectures. With basic building blocks, the size of a complete microfluidic device, which is traditionally limited by costly
master molds in aforementioned fabrication methods, is less restricted. Post-production, building blocks can be rearranged
for a different application or functionality. Individual components can be updated on existing systems, or new modules can
be added on.

Many attempts have been made to construct modular microfluidic devices. However, they all lack at least one of these key
criteria: modularity at the channel level, simple interfacing mechanism, 30 configurability, and mass producibility. For
example, prior patents, "Microfluidics prototyping platform and components" and "Modular microfluidic devices comprising
sandwiched stencils", require fasteners or adhesives to seal individual building blocks. Others, such as "Microfluidic
component capable of self-sealing", utilize even more complicated sealing mechanisms including levers and springs. In the
academic literature, P.K. Yuen et al. described a modular platform in their paper, "Multidimensional modular microfluidic
system". Some disadvantages include the need for a motherboard component, and the method of interfacing is through
luer fittings. Therefore, this system lacks modularity at the channel level. Langelier et al. demonstrated in their paper,
"Flexible castinq of modular self-aliqninq microfluidic assembly blocks", microfluidic buildinq blocks resemblinq puzzle
pieces having interlocking tabs. Downsides here are the need for an adhesive, and the configurations are limited to 20.
Perhaps the most prominent modular microfluidics platform is described in "Discrete elements for 30 microfluidics" by
Bhargava et al. Building blocks snap together and can be arranged in 30 configurations. The main issue is that the building
blocks are 30 printed, a slow process that is costly per part printed. Thus, the resolution of the microfluidic channels is
limited. Further, individual blocks cannot be mass produced, namely through injection molding. This presents a major
problem is biomedical applications, where microfluidic devices need to be as disposable as pipet tips to avoid
contaminations.

Researchers at the University of CA, Irvine have developed modular microfluidic platforms consisting of microfluidic building blocks that can be connected
in various configurations to construct complete microfluidic devices for different applications.

Suggested uses

Platform for manufacturing modular microfluidic chips

Advantages

This platform is modular at the channel level and can support multiple configurations. Also, the mechanism of interfacing and
sealing is as simple as connecting building bricks together. Furthermore, since individual assembly blocks are cast from
master molds, this platform can easily be mass produced, specifically via injection molding. Highly precise injection molds
can yield extremely intricate microfluidic channels and features, which are difficult to achieve with 3D printing. Each
piece can be produced at a much higher rate and at a significantly lower cost than existing platforms, allowing for
commercial availability. Another notable advantage of this platform is that it is
easily integratable into a variety of workflows,
from biology research labs to resource-limited settings and classrooms. Finally, electrodes can be patterned on assembly
block channels as electrical sensors. Electrical interconnections can then be made in between each building block when
the electrodes come into contact, similar to way the microfluidic channels interface with one another.